It is generally known that maloperation during use of a seat belt system can lead to injuries in a case of collision. The most frequent operating error and hence chief cause for such injuries, in particular in the abdominal region, is a “wrong” position of the seat belt, which is neglected by the vehicle occupant or not at all recognized as such. Wrong position here is understood to be a seat belt path on the body of the vehicle occupant, which does not correspond to the respective recommendations of experts in vehicle occupant safety. Ideally, a seat belt should extend over the body of the vehicle occupant such that the upper edge of the lap belt portion lies below the two anterior iliac spines, so that it can act on the bony pelvis rather directly and without a risk of slipping.
A device for protecting a vehicle occupant in a motor vehicle comprising a means for detecting a maloperation during use of a seat belt system by the vehicle occupant is shown in DE 699 24 759 T2. The device includes a belt retractor, which generally can detect an improper use of the shoulder belt and lap belt portions of a seat belt. Monitoring requires an electric field generator means especially provided for this purpose and a modified seat belt in the form of an iron-containing material mounted on the belt or woven into the same.
As regards the retrieval of personal settings in a vehicle—beside the established memory systems, often bound to the vehicle keys, which provide for storing and restoring individual seat, mirror and steering column settings—DE 10 2005 018 078 A1 discloses an expanded system with an on-board information means and a portable storage means. The storage means can be used for storing a user profile with personal actuation data for mechanical and electronic vehicle means (e.g. navigation system, seat adjustment, air conditioning, car radio).
DE 10 2005 007 865 A1 describes a uniform adjusting system for all personalizable vehicle functions. Examples for the adjustable vehicle functions include the activation/deactivation of the passenger airbag and the automatic closing of the doors starting at a defined vehicle speed. The personalized settings are stored in a vehicle key.
From DE 10 2004 040 829 A1, an operating means is known, by means of which a plurality of defaults for certain vehicle elements (driver assistance, inter alia) are selectable in dependence on the current driving situation.
With respect to an adjustment of a vehicle safety system to a vehicle occupant, there are not only known simple sensor systems, which detect the mere presence of a vehicle occupant, but also advanced systems, which allow a rough characterization of the vehicle occupant in terms of weight, size and seat position. Examples for such systems with reference to the control of belt-type restraint systems are described for instance in EP 1 208 021 B1 and EP 1 256 493 A2.
It is an object of the present invention to reliably detect a maloperation during use of a seat belt system.